As portable devices become more compact, and the amount of information to be processed and stored increases, it has become a significant challenge to design a user interface that allows users to easily interact with the device. This is unfortunate because the user interface is the gateway through which users receive not only content but also responses to user actions or behaviors, including user attempts to access a device's features or tools. Some portable electronic devices (e.g., mobile phones) have resorted to adding more pushbuttons, overloading the functions of pushbuttons, or using complex menu systems to allow a user to access, store and manipulate data. These conventional interfaces often result in complex key sequences and menu hierarchies that must be memorized by the user. Indeed, some key sequences are so complex as to require two hands to complete.
Accordingly, there is a need for simpler, more intuitive user interfaces for portable devices that will enable a user to access, store and manipulate graphical objects and data without memorizing key sequences or menu hierarchies.